If you remove a disk from the system using rmdev -dl hdiskX without
having previously reduced the volume group to remove the disk from LVM,
and thus have not updated properly the on-disk format information
(called VGDA), you get a discrepancy between the ODM and the LVM
configurations. Here is how to solve the issue (without any warranty
though!).
What are the volume group informations:
# lsvg -p rootvg
rootvg:
PV_NAME PV STATE TOTAL PPs FREE PPs FREE DISTRIBUTION
hdisk0 active 2157 1019 174..00..00..413..432
0516-304 : Unable to find device id 00ce4b6a01292201 in the Device
Configuration Database.
00ce4b6a01292201 missing 2157 1019 174..71..00..342..432
# lspv
hdisk0 00ce4b6ade6da849 rootvg active
hdisk2 00ce4b6a01b09b83 drakevg active
hdisk3 00ce4b6afd175206 drakevg active
# lsdev -Cc disk
hdisk0 Available Virtual SCSI Disk Drive
hdisk2 Available Virtual SCSI Disk Drive
hdisk3 Available Virtual SCSI Disk Drive
As we can notice, the disk is still in the LVM configuration but doesn't show up in the devices. To solve this issue, we need to cheat the ODM in order to be able to use LVM commands to change the LVM configuration, stored on the volume group disks. The idea is to reinsert a disk in the ODM configuration, remove the disk from LVM and then remove it from ODM. Here is how we do it. First, let's make a copy of the ODM files that we will change:
# cd /etc/objrepos/
# cp CuAt CuAt.before_cheat
# cp CuDv CuDv.before_cheat
# cp CuPath CuPath.before_cheat
Now, we will extract the hdisk0's definition from ODM and add it back
as hdisk1's definition:
# odmget -q "name=hdisk0" CuAt
CuAt:
name = "hdisk0"
attribute = "unique_id"
value = "3520200946033223609SYMMETRIX03EMCfcp05VDASD03AIXvscsi"
type = "R"
generic = ""
rep = "n"
nls_index = 0
CuAt:
name = "hdisk0"
attribute = "pvid"
value = "00ce4b6ade6da8490000000000000000"
type = "R"
generic = "D"
rep = "s"
nls_index = 11
# odmget -q "name=hdisk0" CuDv
CuDv:
name = "hdisk0"
status = 1
chgstatus = 2
ddins = "scsidisk"
location = ""
parent = "vscsi0"
connwhere = "810000000000"
PdDvLn = "disk/vscsi/vdisk"
# odmget -q "name=hdisk0" CuPath
CuPath:
name = "hdisk0"
parent = "vscsi0"
connection = "810000000000"
alias = ""
path_status = 1
path_id = 0
Basically, we need to insert new entries in the three classes CuAt,
CuDv and CuPath with hdisk0 changed to hdisk1. A few others
attributes need to be changed. The most important one is the PVID,
located in CuAt. We will use the value reported as missing by
lsvg -p rootvg. Attribute unique_id also need to be changed. You can
just change a few characters in the existing string, it just need to be
unique in the system. The other attributes to change are connwhere in
CuDv and connection in CuPath. Their value represent the LUN ID of
the disk. Again, this value is not relevant, it just have to be unique.
We can check the current LUN defined by running lscfg on all the disks
defined:
# lscfg -vl hdisk*
hdisk0 U9117.570.65E4B6A-V6-C2-T1-L810000000000 Virtual SCSI Disk Drive
hdisk2 U9117.570.65E4B6A-V6-C3-T1-L810000000000 Virtual SCSI Disk Drive
hdisk3 U9117.570.65E4B6A-V6-C3-T1-L820000000000 Virtual SCSI Disk Drive
LUN 81 is used on controller C2 and LUNs 81 and 82 on C3. Let's choose 85, which for sure will not collide with other devices. The following commands will generate the text files that will be used to cheat the ODM, according to what was just explained:
# mkdir /tmp/cheat
# cd /tmp/cheat
# odmget -q "name=hdisk0" CuAt | sed -e 's/hdisk0/hdisk1/g' \
-e 's/00ce4b6ade6da849/00ce4b6a01292201/' \
-e 's/609SYMMETRIX/719SYMMETRIX/' > hdisk1.CuAt
# odmget -q "name=hdisk0" CuDv | sed -e 's/hdisk0/hdisk1/' \
-e 's/810000000000/850000000000/' > hdisk1.CuDv
# odmget -q "name=hdisk0" CuPath | sed -e 's/hdisk0/hdisk1/' \
-e 's/810000000000/850000000000/' > hdisk1.CuPAth
Let's look at the generated files:
# cat hdisk1.CuAt
CuAt:
name = "hdisk1"
attribute = "unique_id"
value = "3520200946033223719SYMMETRIX03EMCfcp05VDASD03AIXvscsi"
type = "R"
generic = ""
rep = "n"
nls_index = 0
CuAt:
name = "hdisk1"
attribute = "pvid"
value = "00ce4b6a012922010000000000000000"
type = "R"
generic = "D"
rep = "s"
nls_index = 11
# cat hdisk1.CuDv
CuDv:
name = "hdisk1"
status = 1
chgstatus = 2
ddins = "scsidisk"
location = ""
parent = "vscsi0"
connwhere = "850000000000"
PdDvLn = "disk/vscsi/vdisk"
# cat hdisk1.CuPath
CuPath:
name = "hdisk1"
parent = "vscsi0"
connection = "850000000000"
alias = ""
path_status = 1
path_id = 0
So, we are ready to insert the data in the ODM:
# odmadd hdisk1.CuAt
# odmadd hdisk1.CuDv
# odmadd hdisk1.CuPath
# lsvg -p rootvg
rootvg:
PV_NAME PV STATE TOTAL PPs FREE PPs FREE DISTRIBUTION
hdisk0 active 2157 1019 174..00..00..413..432
hdisk1 missing 2157 1019 174..71..00..342..432
The disk is now back in ODM! Now, to remove the disk from the VGDA, we
use the reducevg command:
# reducevg rootvg hdisk1
0516-016 ldeletepv: Cannot delete physical volume with allocated
partitions. Use either migratepv to move the partitions or
reducevg with the -d option to delete the partitions.
0516-884 reducevg: Unable to remove physical volume hdisk1.
We will use the -d flag to remove the physical partitions associated
to each logical volumes and located hdisk1. A few lines have been remove
to simplify listing...
# reducevg -d rootvg hdisk1
0516-914 rmlv: Warning, all data belonging to logical volume
lv01 on physical volume hdisk1 will be destroyed.
rmlv: Do you wish to continue? y(es) n(o)?
y
0516-304 putlvodm: Unable to find device id 00ce4b6a012922010000000000000000 in the
Device Configuration Database.
0516-896 reducevg: Warning, cannot remove physical volume hdisk1 from
Device Configuration Database.
# lsvg -l rootvg
rootvg:
LV NAME TYPE LPs PPs PVs LV STATE MOUNT POINT
hd5 boot 2 2 1 closed/syncd N/A
hd6 paging 256 256 1 open/syncd N/A
hd8 jfs2log 1 1 1 open/syncd N/A
hd4 jfs2 7 7 1 open/syncd /
hd2 jfs2 384 384 1 open/syncd /usr
hd9var jfs2 64 64 1 open/syncd /var
hd3 jfs2 128 128 1 open/syncd /tmp
hd1 jfs2 2 2 1 open/syncd /home
hd10opt jfs2 32 32 1 open/syncd /opt
fslv04 jfs2 256 256 1 open/syncd /usr/sys/inst.images
loglv01 jfslog 1 1 1 closed/syncd N/A
lv01 jfs 5 5 1 closed/syncd /mkcd/cd_images
# lsvg -p rootvg
rootvg:
PV_NAME PV STATE TOTAL PPs FREE PPs FREE DISTRIBUTION
hdisk0 active 2157 1019 174..00..00..413..432
The disk has been deleted from the VGDA. What about ODM?
# lsdev -Cc disk
hdisk0 Available Virtual SCSI Disk Drive
hdisk1 Available Virtual SCSI Disk Drive
hdisk2 Available Virtual SCSI Disk Drive
hdisk3 Available Virtual SCSI Disk Drive
# rmdev -dl hdisk1
Method error (/etc/methods/ucfgdevice):
0514-043 Error getting or assigning a minor number.
We probably forgot to cheat one ODM class... Never mind: let's remove the cheat we added to ODM and see what appends:
# odmdelete -o CuAt -q "name=hdisk1"
2 objects deleted
# lspv
hdisk0 00ce4b6ade6da849 rootvg active
hdisk2 00ce4b6a01b09b83 drakevg active
hdisk1 none None
hdisk3 00ce4b6afd175206 drakevg active
# rmdev -dl hdisk1
Method error (/etc/methods/ucfgdevice):
0514-043 Error getting or assigning a minor number.
# odmdelete -o CuDv -q "name=hdisk1"
1 objects deleted
# lspv
hdisk0 00ce4b6ade6da849 rootvg active
hdisk2 00ce4b6a01b09b83 drakevg active
hdisk3 00ce4b6afd175206 drakevg active
# lspath
Enabled hdisk0 vscsi0
Enabled hdisk2 vscsi0
Enabled hdisk2 vscsi1
Enabled hdisk3 vscsi1
Enabled hdisk3 vscsi0
Unknown hdisk1 vscsi0
# odmdelete -o CuPath -q "name=hdisk1"
1 objects deleted
# lspath
Enabled hdisk0 vscsi0
Enabled hdisk2 vscsi0
Enabled hdisk2 vscsi1
Enabled hdisk3 vscsi1
Enabled hdisk3 vscsi0
That's it! Use with care.
Side note: This entry was originally contributed by Patrice Lachance, which first wrote about this subject.